Motor-starting controller.



T. VARNEY & G. G. TARKINGTON.

MOTOR STARTING CONTROLLER.

APPLIUATION FILED MAYQ, 1911.

Patented Dec. 10, 1912.

WITNESSES:

ATTORNEY UNITED STATES PATENT onmon.

T HEODORE VARNEY, OF PITTSBURGH, PENNSYLVANIA, AND CLARENCE G. TARKING- TON, or CHICAGO, ILLINOIS, ASSIGNORS TO wEs'uNGHousnnLEc'rnIo AND-MANU- FACTURING COMPANY, A CORPORATION or PENNSYLVANIA.

MOTOR-STARTING CONTROLLER.

Specification of Letters Patent.-

Patented Dec. 10, 1912.

Application meana 9, 1911. SerialNo. 626,056.

trollers for electric motors and it has special reference to such controllers as are adapted to controlmotors of very large capacity.

The object of our invention is to provide a s stem of the above-indicated character the shall embody a series of manually closed circuit interrupters provided with mechanically interlocking means to necessitate their closure in a predetermined sequence and with such electrically interlocking means that each circuit breaker shall automatically open the preceding circuit breaker of the series.

For starting electric motors of very large -size, a series of manuall operated switches are sometimes employe on account of the very large currents which are necessarily handled, and such switches are usually mechanically interlocking in such manner that they can only be closed in the pro or sequence', but, as ordinarily arrange they remain closedduring the normal operation of the motor. A

When resistance is employed for securing the necessary voltage control, the above specified arrangement has no serious disadvantages,-but, when the switches are connected to different voltage taps of auto transformers, or other similar regulating means, local short circuited currents are established if two or more of the control switches remain closed at the same time. It is therefore desirable to open each switch as soon as the next succeeding switch is closed.

According to our present invention, we employ a series of circuit breakers of any well known type which are closed manually and are tri ped by an electro-magnet. We mechanics. interlock the breakers in such manner tha, they are ne essarily closed in the proper order, and, as each breaker in the series is closed, the circuit of the trip coil for the preceding breaker is also closed.- While, as above indicated, the system is especially adapted for starting alternating .current motors, it may be .found advantageous for starting large direct current motors when it is desired to quickly reinsert the starting resistance in case of an overload on the circuit.

Figure 1 of the accompanying drawings is a diagrammatic view of a starting controller of our invention. applied to a polyphase alternating current motor. Fig. 2 is a detail view illustrating 'a simple means of mechanically interlocking the circuit breakers of Fig. 1, and Fig. 3 is a view corresponding to Fig. 1 that shows the applica tion of ourmotor starter to a direct current motor.

Referring to Fig. 1 of the drawings, alternating current energy is supplied -from any suitable source (not shown) through conductors 1, 2 and 3 to an induction motor 4, transformer windings 5 and 6 being utilized for reducing the volt-age ap lied to the motor at starting. The transihrmer winding 5 is connected ,across thecircuit conductors 1 and\ 2, and the transformer winding 6 is connected across conductors 2 and 3,

each of the windingsbeing provided with taps 7, 8 and 9. The motor jcerminals 10,

'11 and 12 are respectively connected, during the normal operation of the motor, torline conductors 1, 2 and 8 through conductofi 13, 14 and 15. In starting the motor, a circuit breaker 16 is first closed, energy then being supplied to the motor from the taps 7 of the transformer windings 5 and 6, through contact members 17 and 18 of the circuit breaker, conductors 19 and 20 and conductors 13 and 15 to the motor terminals 10 and 12, the terminal 11 being connected directly to the line conductor 2 through a trip coil 21' of a circuit breaker 22. The motor is thus started by 'an application of relatively low-voltage current to its windings. The circuit breaker 16 comprises a closing handle 23, a contact-bearing member 24, and interposed links 25 and 26. The

handle 23 is provided with a projection 27 v whi'h is brought into engagement with the link 26 in closing the breaker. "A stop 28 prevents the links from collapsing after the breaker has been mrived into its closed position, and a core member 29 is adapted to trip the breaker when actuated by a trip coil 30 in opposition to a spring 31.

As shown in Fig. 2 of the link 25 of the breaker moves into engagement with a pawl 32 of an interlocking rod 33, the arrangement of parts being such that the rod is moved longitudinally in the direction of the arrow 34-. and in opposition to spring 35 when the breaker is closed. When it is desired to further accelerate the motor, circuit breaker 3G is closed, energy then being supplied to the motor terminals 10 and 12 from thetransformer taps 8. The circuit brea er 36 is provided with an auxiliary contact member 37 which bridges contact members 88 and completes a circuit, when breaker 36 is closed from a terminal 39 of a transformer 40, which may be re placed by any suitable auxiliary source of current, throughconductor 41, contact members 37 and 38, trip coil 30 of circuit breaker 16 and conductor 42 to the opposite terminal 4:3 of the transformer. It is, therefore, evident thatthe breaker 16 is opened immediately upon the closing of the circuit breaker 3G and, consequently, the transformer sec tions between the taps 7 and 8 are only short circuited for a very short time. The circuit breaker 36 is similar to the circuit breaker 16 and, as shown'in Fig. 2, the rod 33 is provided with a pawl 44 which is so formed and so placed that the breaker 36 can only be closed after the breaker 16 has been closed. The circuit breaker 22 connects the motor terminals 10 and 12 directly to the line conductors 1 and 3. and is provided with an auxiliary contact member 45 which completes a circuit through trip coil 46 of the circuit breaker 36. The rod 33 is further provided with a pawl t? which prevents the circuit breaker 22 1"r0m being closed until the circuit breaker 36 has been closed. Briefly, the action. of the control switches to gradually apply increased voltages to the motor terminals by a series of steps, the circuit connections for each step being interrupted. as soon as the next succeeding step completed. The trip coil 21 of the circuit breaker 22 above indicated, connected in series relation to line conductor 2 so that. if the current traversing the motor circuit exceeds a predetermined amount, the circuit breaker will be opcned'and the motor circuits entirely interrupted. In order to reaccelerate the motor, it will be necessary to again close the circuit breakers 16,36 and 22 in the order named, as before.

Referring to F g. 3 of the drawings,.a

direct current motor having an armature 48, a field magnet w nding 49 and starting redrawings, thev sistance 504s governed by a series of circuit breakers 51 t6 55, inclusive, which are similar to the circuit breakers shown in Fig. 1

and are preferably interlocked in the same manner. The action of the circuit breakers is to gradually short circuit the resistance 50, each breaker serving to open the preceding breaker. Circuit breaker 55, which is the last to be closed, is provided with a trip coil 56 that is connected in seriesrelation to the motor circuit and serves to reinsert the starting resistance in case the current traversing the motor circuit exceeds a pre determined amount.

Our motor controller .may be applied to the control of various electric machines, and we desire that only such limitations shall be imposed as are indicated in the appended claims.

'We claim as our invention:

1. In a motor starter, the combination with a plurality of manually closed switches and tripping coils therefor, of means for restricting the closure of said switches to'a predetermined sequence, and means depend ent upon the closure of each of the switches, except the first, for energizing the tripping coil of the preceding switch. V

2. In a motor starter, the combination with a plurality of main switches and trip ping coils therefor, of means for restricting the closure of said switches to a predetermined scquencc, and an auxiliary switch operated by each main switch, except the first, to close the circuit of the tripping coil of the preceding switch.

3. In a motor starter, the combination with a plurality of main switches and tripping coils therefor, of means for restricting the closure of said. switches to a predetermined sequence, an auxiliary switch operated by each main switch, except the first, to close the circuit of the tripping coil of the preceding switch, the tripping coil of the last switch being dependent upon predetermined conditions in the motor circuit.

at. The combination with an electric motor, a supply circuit therefor, and a series of motor-starting switches adapted to be manually closed in a predetermined sequence, of means for opening each switch upon the closure of the next succeeding switch, and means dependent upon predetcrmined conditions in the motor circuit for opening the last switch of the series.

5. The combination with an electric motor, asupply circuit therefor, and a series of motor-starting switches adapted to be manually closed in a predetermined sequence, of means for opening each switch upon the closure of the next succeeding switch, and means dcpcndent upon the current traversing the inotorcircuit for opening the last switch of the series. i

6. The combination with an electric motor,

a supply circuit therefor, a series of control switches for the motor that are mechanically interlocked to preclude the closure of the switches except in a predetermined sequence, of a trip coil for each switch, and auxiliary switches operatively connected to each of the switches except the first; the trip coils of each switch, except the last, being energized when the auxiliary switch of the next succeeding switch of the series is closed-and the trip coil of the last switch of the series being energized to open the, switch only when the current traversing the motor circuit exceeds a predetermined amount.

Copies of this patent may be obtained for five cents each; by addressing'the In testimony whereof, I have hereunto l subscribed my name this 25th day of April,

In testimony whereof, I have hereunto subscribed my name this 18th day of April,

CLARENCE Gr. TARKINGTQN.

Witnesses CLARENCE T. WEIR,

D. B. HUTCHINSON.

Commissioner of Patents,

Washington, D. G. 

